Safety mechanism for hanging scaffolds



Wm A

June 7, 1960 F. PUTTRE Filed April 1, 1957 SAFETY MECHANISM FOR HANGING SGAFFOLDS INVENTOR FERDINAND PUTTRE q Qw RNEY.

States PatentfO This invention relates to a safety mechanism for hanging scaffolds. The object of this invention is the provision of a safety device which may be used in conjunction hanging scafiolds to prevent them from falling when the ropes which suspend them happen to break. Reference is here made particularly to scafiolds used by house painters. These scafiolds are suspended by ropes from hooks or other supports which aresecured to the roof of a building. \It has happened that ropes usedfor this purpose have given way while in use, causing injury and ingv in which:

members are a pair of wedges which ride against inclined planes into and out of engagement with the ropes.

The term rope as used herein is intended to include ropes, cables, chains and the like.

The invention is illustrated in the accompanying draw ice Fig. l is a fragmentary front view of a scaffold which is adapted to be suspended or hung by ropes from the roof of a building and which is provided with a safety device made in accordance with one form of this inven- I j, tion.

Fig. 2 is an end view thereof.

Fig. 3 is a fragmentary view of another scafiold of like nature showing a safety device incorporated therein and made in accordance with a second form of this inveneven death to'those using the scaffold at the time; It'has 5.

also happened that persons'us'ing such scalfolds have'lost control of these nopeswhile operating them during ascent orv .descent of the scaffolds, with the same serious consequences.

The present invention provides safety means operating J independently of the ropes from whichthe scaffolds are suspended. In the operation of this safety means, it is immaterial whether the ropes [from which the scaffolds are suspended fail in use or whether they simply pull out Of the Control Of 11685 attempting 19 them- In should be strongly secured to the scafiold. The secureither of these cases, an auxiliary supporting means. autom-atically takes over and supports the scaffolds without any conscious or active participation on the part of those who are using the scafiolds.

' More specifically, two, auxiliary ropes or cables are provided, one at each end of a typical scaffold, the two ropes being supported at their-upper ends from the roof ofa building, and being engagedby apair of stopmem hers on the scaffold; These stop members prevent downward movement of the scaifold relative to the ropes except when the stop members are disengaged from the ropes by the persons on the scaffold. The moment the stop members are released, they automatically re-engage the ropes and further downward movement of the scatfold relative to said ropes is prevented.

The stop members to which reference has just been made are eccentric jam elements which become jammed or wedged. into certain unyielding positions upon downward movement of the scaffold relative to the ropes. In these positions, they prevent further downward movement of the scaffold. The only way to terminate this jamming or wedging action is to disengage these stop members from the ropes and this can only he done by a deliberate efiort by those who are 'on the scaffold.

Scaifold 10 shown in the drawing is intended to represent any conventional scaffold suspended by ropes from thereof of a huilding and used by house painters, sign painters and other workers who engage in construction work or maintenance or repairs on the outside of build-- ings which are tootall to-be serviced by ladders. The scaffold is supported at its ends by a strong metal hanger orzframe 12. This hanger or frame serves as a saddle for the scaflold and at its upper end it is connected by means of a hook 14 or the like to a tackle block or pulley 16. Said tackle block is connected by means of rope 18 to a hook-shaped member 20 and a second tackle block 22, said hook-shaped member being adapted to .be hooked to the roof of a building. The foregoing is all conventional. Secured to the scaffold is the safety mechanism herein claimed.

Mounted on the scaffold at each end thereof is a pair of uprights 30 and 32 respectively. These uprights should possess considerable structural strength. and

ing means may be conventional and may consist'ofthe usual nuts and bolts and braces. It will be observed that these uprights 30 and 32 are positioned on opposite sides of a rope 34. The rope is supported at its upper end from a hook-shaped member 21 corresponding to hook 20 which supports ropes 18. Rotatably mounted on upright 32 by means of pin 36 is an eccentric 38. This eccentric may simply be, a disc which is mounted oflE-center for angular movement about pin 36.

Opposite eccentric 38 is the upright 30 and it will be. noted that an arcuate cutout 40 is provided in said up-. right to receive the eccentric 38. It will also be noted that rope 34 rides upon eccentric 38 between said eccentric and the arcuate portion of upright30, along its arcuate cutout 40. A spring 42 is connected at one end to upright 30 and at its opposite end to eccentric 38 and itsaction is 'tov pull the eccentric in clockwise direction as viewed in Fig. 1. This would tend to bring the against the arcuate portion of upright 30.

A-lever 44 is secured to eccentric 38 by means of pin- 36 and a second pin 37. A weight 46 is provided on lever 44 and said weight tends to swing the lever downwardly about the axis of pin 36 and this has the effect ofurging eccentric 38 to move in clockwise direction. precisely as it is caused to move under the influence of spring 42. Either the; spring alone or the weight alone would normally suflice for this purpose but the two are provided as an added safety precaution.

A pad 50 is secured to the scaffold 10 adjacent each upright 32. Pivotally mounted on said pad is a pedal 52. A cable 54 is secured at one end to said pedal and at its opposite end to the lever 44. Intermediate its ends, the cable 54 rides on a pulley 56 which is rotatably mounted on upright 32 above lever 44. The pedal may be de pressed to pull cable 54 and thereby to cause the lever 44 to swing in counter-clockwise direction, as viewed in r Fig. 1, about the axis of pin 36. Since the lever is secured to eccentric 38, this causes the eccentric to swing in counterclockwisedirection out of engagement with the rope 34. This actiontakes place against the influence of spring 42 and weight 46 and it frees the scaifold' fpr movement relative to the rope 34; When, the pedal 52 is released, spring .42 and weight 46"will' automatically swing the eccentric in clockwise direction back into engagement with the rope, thereby jamming-the rope between the eccentric and the arcuate portion of upright- 30 and preventing movement of the scaffold relative to saidrope 34,

be to pull the wedge down along the inclined plane 70 and out of engagement with rope 66. This would be done against the action of spring 74 and weight 92 and the result would be to free the scaffold for movement relative to the rope 66. When it is desired to re-engage the rope and to prevent such relative movement between the scaffold and the rope, pedal 82 is released and spring 74 and weight 92 will act upon the wedge to move it upwardlyi'nto iamrn'ingv engagement against the rope. Small ridges 98 may be formed on the side of upright 62 which faces rope 66 directly opposite the wedge 72 andcorresponding ridges 99 may be formed on that side of the wedge which also faces-the rope. Jlhese ridges serve to Referring now to the second form of thisinvention and to Fig. 3, it will be understood that scaffold 60 in 3 is intended to correspond'to scaifoldZO in Fig-L 1* and to represent a conventional scaffold. 'At each end of scafiold 601's the conventional supporting means fonsupporti'ngit e from the roof of a building but t-his is not shown in the drawing both for the reason that it is conventional and forthe further reason that showing itwould tend to confuse the disclosure of the inventive features of the invention.

At each end of scaffold 60 is an upright 62 and a sec ond upright 64. These two uprights are securely fastened to the scaffold and it will be noted that they are spaced apart to accommodate a rope 66 between them. This rope 66 corresponds to rope 34 above mentioned and it is the auxiliary or safetyrope whichis designed) support the scaffold upon failure ofthe conventional supporting means.

There isa cutout 68 in upright 64 and along-said cutoutis a diagonal wall 70 whichserves in the present: invention as aninclined2plane. Slidably supported in the cutout 68-, against-the inclinedplane 70 is a w edge 72. A spring This-connectedatone end tothe top of said upright 64' and at its opposite end to the wedge 72 and it tends to urge the wedge. upwardly along said inclined plane 70. It will beobserved that this upward movement of the wedgeagainst theinclined plane brings'it intoengagemenb withrropei66 and jamsthe rope against upright 62. This locks'thescaifold against movementi-elative-to said rope.

A pad180 is-secured to scaffold 60 at eachend thereof. A pedal 82 ispivotally. supported on said pad; A cable 84 is connected at one end'topedal 82 and at its opposite end toalever 86. This lever is pivotally supported on upright- 64, by.; means ofpin' 88. Atoneend of 'lever-86 is a bar 90- which is pivotallysecured at its lower end to said" lever- 86-and at its-upper endto wedge 72 A weight 92 is secured to lever 86 at-the oppositeend Ofsaidleverfrombar9tl. It will now be understood that'the action of-weight. 92 is to swing lever 86 in clockwise direction asviewed inFig. 3. This movementcauses the bar 90' to movelupwardly and to push the wedge 72 upwardly along the inclined plane. 70; Itis therefore clear that weight92- and'spring-74 both perform the same function with respectto wedge-72; and that is to move the-wedge upwardly-along the inclined plane intojamming engagement with the rope. 66.

When-it is desiredto releasewedge- 72 from rope 66', pedal 82 is depressed; It will'nowbenoted'that cable 84: n'des;onpulley; 96: which is; supported on upright 64.

Sinceofieendaofthe cable is-secured to thepedal 82 and the-.opposite end-'is secured to lever 86, depressing the pedal will cause' the cable-84 to pull lever 86 in counterclockwise direction as viewedin Fig 3. Since said'leverisiconnected towedge 72'bymeans-of bar 90, the effect 0-=this counter-clockwise.movement h of theleverwould increase the frictional engagementbetween the wedge 72 and upright 62 on the 'one'hand and the rope 66 on the other.

The foregoing is illustrative of preferred forms of this invention and it will be understood. that the preferred forms may be modified and other forms may beprof vided within the broad spirit of the invention and the broad scope of the claim.

A brake device for rope-suspended scaffolds and the like, comprising a pair of uprights, said pair of uprights being spaced apart to receive a rope between them, and wedging means on the first of said pair of uprights adapted to engage and wedge the rope against the second of'sai d pair of uprights, release means being provided in connection with said' wedging means to disengage" said wedging means from the rope, said first upright being provided with a sloping surface facing the rope, said sloping surface being adapted" to function as an inclined plane, the wedging means comprising a wedge having one edge sliding on the inclined plane. surface of said first upright and the other edge facing the rope, being parallelto the rope andengaging the same, said wedge being movable in one direction to jam the rope against said secondup'rightandi movable in the opposite direction out of jamming: engagement with said rope; a spring being. connected between the wedge and said first upright" to urge the wedgeinto-j'amming engagement with the rope; apivoted l'ever'being also provided on said' first upright and a link betweenone end of said lever and thewed'ge, a weight being provided at the opposite end ofsaid'lever and acting to swingthe lever in such direction as to-cause the-link to urge the-wedge into jamming engagement Withthe rope, thereby complementing the acting'of said spring, said release means comprising a pedal, a pulley" being provided onsaid first upright and a cable extending around said' pulley,= said-cablebeing connected at one end to the pedal and at the opposite end to the lever, whereby depressingthepedal causes the'cable'to pullupon the lever and to' swing the lever in the opposite direction from the-dircction in which-it is urged by thespringand Weight, thereby withdrawing-the wedgefrom jamming engage= ment with the rope References: Citediin the :file :of'this patent UNITED STATES PATENTS 1,401,991. Lehr Jan. 3', 192-2 1,412,624 Lundgren Apr. 11, 1922 1,921,627 Lucchesi; Aug.,8-, 1933' 2,066,094 Crawford ...Dec. 29,1936

2,268,050 McIntosh Dec. 30, 1941 FQR'EIGNT PATENTS 85749 Norway" May' 21; 1954 

